This invention relates to space dyeing apparatus and more particularly to apparatus for applying dye to a plurality of yarn strands in a preselected array or pattern of color, spacing and length in a continuous manner and for selectively controlling the array, spacing and amount of dye applied to the yarn.
In some fabrics, such as carpets, it is desirable to provide yarns which have a color pattern varying along their lengths. Such yarns have come to be known as space-dyed yarns, and apparatus and processes for coloring such yarn are known as space-dyeing apparatus and processes. Carpet fabrics made from yarns of this type generally have a multicolor effect with no visible pattern. Various space-dyeing methods and apparatus have been known in the prior for some period of time. See for example, Epstein U.S. Pat. No. 2,573,097. Such methods and apparatus include systems where a number of yarns pass over a series of dye applicator rollers or drums which are charged with dyes of various colors. The yarns generally are controlled during passage over the drums so as to maintain clearance with the surfaces except when it is desired to color a portion of the yarn. When a portion of the yarn is to be colored the yarn is depressed by a presser member to cause the yarn to be pressed against the surface of the selected dye applicator roller. The presser member may be a piston or plunger reciprocating above the dye applicator roller for forcing the yarn directly against the periphery of the dye applicator roller as disclosed in Farrer et al U.S. Pat. No. 3,503,232 and Worth et al U.S. Pat. No. 3,879,966, or may be a series of pads mounted on a rotating drum, the pads forcing the yarn against the dye applicator roller as in Keown U.S. Pat. No. 3,541,958. Thus, in the prior art the yarn is stamped, impacted or hammered against the dye applicator roller. If the plunger or pad is held against the yarn for too long a time, the feeding of the yarn may be impaired. Thus, the amount of dye applied to the yarn during each impact is limited.
In Farrer et al and Worth et al the speed of the dyeing is limited because of the limitations on the reciprocating elements including the cycling and the acceleration forces involved.
In the Keown and Worth et al patents the yarn is precolored with a base color and the stamping effectively results in the dye applicator rollers applying spots of secondary color on the precolored yarn. Complicated control systems, both mechanical and electrical, are proposed for varying the spacing between the secondary colors applied. In Farrer et al random repeat may be obtained by an electro-mechanical system of cams and switches for controlling solenoids which act as plungers. Such complicated control systems were apparently proposed because the stamping, impacting or hammering of the yarn only applies color to the yarn during that limited portion of the cycle when the yarn is disposed between the piston, plunger or pad and the dye applicator roller.
When a pattern change or change in variegation of colors along the yarns is desired, Keown appears to require a major overhaul or replacement of elements and Worth et al requires replacement or reprogramming of electrical circuitry. Only Farrer et al requires a repositioning of mechanical members which form raised portions on the surface of cylindrical cams and thus can be performed by non-highly skilled maintenance personnel. However, such repositioning of cam elements merely effects the engagement of the plungers which force the yarns against the dye applicator rollers which include the aforesaid limitations. Moreover, since the cam elements act to control micro switches which activate the plungers, and the switches may open and close a number of times each revolution, switch maintenance and replacement may be common.